Origin & History of “secure”

Something that is secure is etymologically ‘carefree’. The word was borrowed from Latin sēcūrus, a compound adjective formed from the prefix sē- ‘without’ and cūra ‘care’ (source of Englishcurate, cure, etc). The metaphorical extension from ‘free from care’ to ‘free from danger, safe’ took place in post-Augustan Latin. Sure is in effect a telescoped version of secure.